The City of Key West, Florida

The Southernmost City in the Continental United States


Building Height Exception

On Nov. 4, 2014, Key West voters approved The Building Height Referendum.

Existing buildings below established flood levels will be able to exceed the height restriction on the top by the number of feet added to the bottom to elevate/construct a building to the flood level, with up to an additional four feet of freeboard.

New construction may voluntary elevate above the minimum required level, and exceed the building height restriction by up to three additonal feet.

Buildings located within the "X" and "Shaded X" flood zones aren't affected by this change, because there aren't any established flood levels in these zones and construction isn't regulated by the floodplain ordinances.

New:  Building Height Exception Guidelines.

New:  Building Height Certificate  [To be completed only by land surveyors]

Non-Conversion Agreement 

Non-Conversion Agreement (fillable ver.)


Question:  Will this allow me to build a taller building?

Answer:  No. The building height exemption was added to the existing ordinance, but didn’t change other provisions already in the ordinance.  Thus, the building size limitations - which governs how tall the physical size of a building may be - remain the same.


Question:  How high can I elevate my building?


Existing Buildings:  This is simpler to understand with an existing building that's going to be elevated.  It's the distance from the ground to the Base Flood Elevation (BFE) level, plus up to a maximum of four additional feet.

The BFE level differs by location.  In some instances, buildings on a single lot may have different BFE levels if a flood zone line runs through the lot.  (See How to Read Flood Maps.)

Determining how high above ground the minimum flood level (BFE) is for any site can't be determined until it's known how high above sea level the land is at. The level of the grade is usually determined by obtaining an Elevation Certificate for the location or building from a land surveyor

Example #1: If an Elevation Certificate shows a building is located within an "AE-6" flood zone, and the land is four-feet above sea level, then the BFE is two-feet above the ground (4' + 2' = 6').

Example #2: If an Elevation Certificate shows a building is located within an "AE-8" flood zone, and the land is three-feet above sea level, then the BFE is five-feet above the ground (3' + 5' = 8').

New Construction: There are now minimum elevation standards for new buildings.  The Building Height Exception doesn't being to be calculated until those minimums are exceeded. Given that the maximum exception is Base Flood Elevation (BFE) plus four-feet, a maximum three-feet of height exception is possible.

Example 1:  Where the minimum standard is BFE +1', a building constructed to this height wouldn't be eligible for any height exception.

Example 2:  Where the minimum standard is BFE +1', a building constructed to BFE +2', it would be eligible for a height exception of one-foot.

Example 3:  Where the minimum standard is BFE +1', a building constructed to BFE +4', it would be eligible for a height exception of three-feet.


Question:  Why the extra four-feet above Base Flood Elevation (BFE)?

Answer:  The BFE's are minimum expected flood levels. Deeper flood levels are possible. Additionally, there are substantial flood insurance discounts for every additional foot above BFE (known as freeboard)... up to a maximum four feet. 

Note:  The current building code requires new and Substantially Improved buildings be elevated to BFE +one-foot.  This height is referred to as the Design Flood Elevation (DFE).  By default, these buildings end up having a minimum one-foot of freeboard.



Question:  Can I raise my building so the first floor is higher than four feet above the flood level.

Answer:  No. The exception only approved a maximum first floor height of 4’ above the flood level. No City official, board or commission has the authority to allow this to be exceeded.  Only another public referendum could change this limitation.



Question:  The referendum said buildings could be as tall as 40-feet, so why can't I build a 40-foot building?

Answer:  The referendum was designed to assist with the elevation of buildings above flood levels, not to allow the construction of larger buildings. The regulated size of buildings hasn't changed, only how high those same sized building may be elevated.

The 40-foot cap is to ensure that no matter what else may be calculated towards elevation, anything above 40-feet isn't permitted.  

For example: Suppose it's calculated that the maximum a building might be elevated at the bottom - to the Base Flood Elevation (BFE) plus four-feet - would be ten-feet above the ground. However, if adding 10-feet to the bottom of the building would cause the top of the building to be at 42-feet, then the building may only be elevated eight-feet, to the 40-foot limit.


Question:  Where is the building measured from?

Answer:  Three different places, depending upon what measurement is needed.

1. Building Envelope (physical size of the building):

From the bottom of the building (usually bottom of the floor joists) to the highest part of the building. 

Note: If the area under a building - including freeboard area - is enclosed more than 299sf, this becomes the lowest floor and contributes to building size. 


2. Flood Elevations:

Type "A" Flood Zones:  From sea level (NGVD) to the top of the first finished floor.

Type "V" Flood Zones:  From sea level (NGVD) to the bottom of the lowest horizontal supporting cross-member.

(Caution: If built incorrectly, a concrete slab in a V-zone could be ruled the lowest horizontal supporting crossmember and the entire building would then be considered below flood; regardless of how high the first floor was built.  Ask before you build.)


3. Building Height:

From the crown-of-the-road (at the highest point of the closest street adjacent to the building) to the uppermost part of the building.


Question: Why am I confused?

Answer:  It's easy to be confused, because at first blush we're trying to reconcile three different measurements that aren't directly related to each other:

  • Height of the first finished floor relative to Base Flood Elevation
  • Total height of the building relative to the crown-of-the road, and
  • Physical size of the building. 

The only way to reconcile these different measurements is to measure all the relevant heights to one common basis... sea level (a/k/a NGVD).

The following diagram, shows the basic measurements necessary to evaluate utilizing the Building Height Exception. These measurements are all relative to sea level.


1) Height of the first finished floor relative to Base Flood Elevation: 12'


2) Total height of the building relative to the crown-of-the road: 30.041'


3)  Physical size of the building: 34.23'-11'= 23.23'

 This 8-minute animation explains the Building Height Exception.  Even though it was produced before the referendum was approved, it offers another understanding of this new option:

A 4-minute animation explaining flood zones and cost savings associated with elevating buildings located in flood zones.






Contact Us

Scott Fraser,
FEMA Coordinator/Floodplain Administrator
Building Department
1300 White St
Key West, FL 33040
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